For the uninitiated, cr0 is a control register in the x86 family of processors. Bit 16 of that register is (according to wikipedia) WP - Write protect: Determines whether the CPU can write to pages marked read-only.
What this means is that the kernel can no longer see if a user is writing to a read-only location, which is a major part of memory protection. It has major security implications. I don't know whether other parts of the kernel enable or disable this at context switches or at other times.
What this also means is that this kernel module will only work on x86 CPU's. So no rickrolling you ARM boxes or smartphones.
> What this means is that the kernel can no longer see if a user is writing to a read-only location, which is a major part of memory protection.
No, disabling WP in CR0 is only relevant for privileged code. Writes to write protected pages in user mode will still trap. It might mess up some in-kernel COW stuff though.
What this means is that the kernel can no longer see if a user is writing to a read-only location, which is a major part of memory protection. It has major security implications. I don't know whether other parts of the kernel enable or disable this at context switches or at other times.
What this also means is that this kernel module will only work on x86 CPU's. So no rickrolling you ARM boxes or smartphones.